Couplings with self-sealing valves are commonly utilized in fluid circuits to prevent the escape of fluid when the parts are uncoupled. Such self-closing valves are usually spring biased, and are located within the coupling part adjacent the end thereof whereby the valves of the parts engage during coupling to displace each other and open the part passages. Such self-sealing couplings are easily connected if the fluid pressure within a part, or parts, is nil or low, but internal pressure renders coupling of self-sealing parts difficult if the internal fluid pressure must be overcome to displace the valves and permit complete interlocking of the parts.
Fluid couplings used with agricultural equipment must be readily coupled and uncoupled, self-sealing, and of the "breakaway" type wherein the coupling parts automatically separate when the axial tension in the hose lines reaches a predetermined force, as will happen if the implement being towed by the tractor is inadvertently dehitched, or the hitch trips because the implement strikes an immovable object.
Also, with agricultural hydraulic systems it is not uncommon for high pressures to exist within the supplied implement circuit wherein fluid pressure is produced by the weight of the implement hydraulically-operated components. In such instances the pressure within the implement circuit renders interlocking of the coupling parts difficult due to the implement pressure and the supply pressure at the tractor.
Available hydraulic fittings for agricultural systems have not successfully overcome the aforementioned problems, and it is the purpose of the invention to provide a fluid fitting which is capable of overcoming the aforedescribed situations.
It is an object of the invention to provide a fluid coupling which is of the "breakaway" type utilizing self-sealing valves but is capable of transmitting and operating at high fluid pressures, and wherein the valves do not inadvertently close or check due to high volume flow.
Another object of the invention is to provide a fluid coupling wherein the interconnection of the coupling parts is achieved by a manually operated lever, and coupling of the parts is assisted by the hydraulic pressure within the pressurized supply circuit.
A further object of the invention is to provide a self-sealing fluid coupling utilizing standard interfaces, and wherein interconnection of the parts is hydraulically assisted.
Yet another object of the invention is to provide a "breakaway" self-sealing fluid coupling wherein the coupling parts each contain self-sealing valves, and fluid pressure within the supply part is utilized to unseat the self-sealing valve within the supplied part permitting mating and interlocking of the coupling parts regardless of the fluid pressure within the supplied circuit.
In the practice of the invention the female coupling part is connected to the supply side of the circuit utilizing a pump, while the male coupling part communicates with the supplied circuit. The coupling parts utilize standard interface configurations, and an annular sleeve mounted upon the female part utilizes radially movable balls to connect to the male part and a manually operated lever axially translates the sleeve to draw the male part into the female.
An expansible chamber motor is defined in the female coupling part communicating with the supplied pressurized fluid during part interconnection to assist in the axial displacement of the sleeve and operation of the lever.
The self-sealing valves within the female and male coupling parts engage during interconnection, and the female part includes an expansible booster motor in communication with the supplied pressure for displacing the male self-sealing valve if the pressure within the supply circuit is too great to permit the self-sealing valve to open during mechanical interconnection. This booster motor assures opening of the supplied circuit regardless of the static pressure therein.
The sleeve may be displaced by the tension within the coupling parts to provide a "breakaway" operation, and the aforementioned structure is concisely incorporated within a coupling configuration and size comparable to available couplings for similar applications.